Spokeswoman JoEllen Smith says 53-year-old Castro was found hanging in his cell around 9:20 p.m. Tuesday at the Correctional Reception Center in Orient. Prison medical staff performed CPR before Castro was transported to a hospital, where he was pronounced dead.

Just last month, Castro was sentenced to life in prison plus 1,000 years on his guilty plea to 937 counts including kidnapping and rape.

At the time of his death, Castro was in protective custody on suicide watch. Authorities were supposed to check in on him at least every 30 minutes. It is not immediately known what he used to hang himself.

Here is the official statement from the Ohio Department of Corrections: